Challenges and Innovations in the Fabrication of Soft Pneumatic Actuators: A Survey of Current Techniques

Article information

Int. J. Precis. Eng. Manuf.-Smart Tech.. 2025;3(2):161-172

Publication date (electronic) : 2025 July 1

doi : https://doi.org/10.57062/ijpem-st.2024.00213

Altair Coutinho ¹, Jae Hyuck Jang ¹, Yeong Jae Park ¹, Sewoong Chung ¹, Hugo Rodrigue ¹^,²

¹School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea

²Department of Intelligent Robotics, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea

Hugo Rodrigue: rodrigue@skku.edu

Received 2024 October 22; Revised 2025 June 16; Accepted 2025 June 16.

Abstract

Soft robots have been used in a wide range of applications ranging from soft grippers to underwater robotics and a wide range of actuation methods have been used to drive these robots. However, the most commonly used type of actuation is soft pneumatic actuation. Soft pneumatic actuators can be made from polymers, plastics, thin films, etc. and there is an intrinsic relation between their materials, manufacturing method, design and capabilities. This review paper surveys the current manufacturing methods for soft pneumatic actuators and robots, a key component in the growing field of soft robotics. These flexible and adaptable devices rely on pressurized air to achieve movement, with potential applications in healthcare, industrial automation, and human-robot interaction. The paper explores various fabrication techniques, including casting, 3D printing, and sealing, highlighting their respective material requirements and design limitations. Each method impacts the actuator’s flexibility, durability, and performance. The review underscores the need for future research into novel materials and scalable manufacturing techniques to advance the practical deployment of soft robotics across industries.

Keywords: Soft robot manufacturing; Polymers processing; Thin film sealing; 3D printing; Soft pneumatic actuators; Soft robotics

1 Introduction

Soft robotics has emerged as a rapidly growing field within the field of robotics, driven by their potential to revolutionize a wide range of industries. Unlike traditional rigid robots, which are constrained by mechanical joints and hard materials, soft robots are constructed from flexible, compliant materials that allow for more versatile, adaptive, and safe interactions with humans and environments [1–3]. This unique capability positions them for applications in healthcare, wearable devices, soft gripping, search and rescue, and more.

Different forms of actuation methods have been used to drive soft robots including a wide range of smart materials including shape memory alloys and dielectric materials [4], but the most frequently used method of actuation for soft robots is through pneumatic actuation. Soft pneumatic actuation provides a reliable way to achieve large, controllable deformations by inflating and deflating air chambers, which results in smooth and continuous movements.

Despite their popularity, the manufacturing processes behind soft pneumatic systems present unique challenges. Traditional manufacturing techniques, which are designed for rigid robots made from metals and hard plastics, often fail when applied to the soft, flexible materials required for pneumatic actuators. These materials, such as silicone elastomers and thin films, demand specialized approaches to design and fabrication that consider their particularities.

A critical requirement for soft pneumatic actuators and robots is the creation of an airtight chamber, as their function depends on controlled changes in internal volume and pressure to produce movement. If the chamber is not properly sealed, air will escape, rendering the actuator ineffective. The process of constructing this airtight chamber varies significantly depending on the manufacturing technique employed. Furthermore, the performance of the actuator or robot will also depend significantly on the material used, of which the selection is intrinsically linked to the manufacturing method, and the design of the structure, which is limited by the manufacturing method.

This review paper surveys current manufacturing methods for soft pneumatic actuators and robots by relating the limitations of each manufacturing method with the materials used and the resulting design choices. It will cover casting-based, 3D printing-based, sealing-based, and other manufacturing methods for manufacturing soft pneumatic actuators and robots. The paper surveys specific differences and variations in manufacturing methods and how this impacts the design of the device. Each of these methods offers unique advantages and trade-offs, depending on the type of material, the complexity of the actuator design, and the desired application.

1.1 Literature Search Strategy

To ensure a comprehensive and representative overview of the current state of manufacturing methodologies for soft pneumatic actuators, an extensive literature search was conducted. Primary databases used included IEEE Xplore and Google Scholar. Application keywords such as “soft pneumatic actuators and soft robotics were combined with manufacturing-related keywords such as casting, 3D printing, film, and knitted were used in various combinations to refine results. Articles were initially screened based on relevance to manufacturing techniques, material usage, and actuator design outcomes. Previous references were analyzed as well as seminal papers to ensure a broad overview of manufacturing methods within the field. Selected literature was then categorized into four main manufacturing strategies: casting-based, 3D printing-based, sealing-based, and alternative or hybrid methods. Within each category, papers were further grouped by fabrication technique, material type, and application focus.

2 Casting-based Pneumatic Robots

The most common category of materials used to build soft pneumatic robots and actuators is polymers, such as EcoFlex (Smooth-on), DragonSkin (Smooth-on), and polydimethylsiloxane (PDMS). These materials can stretch and deform such that their deformation upon pressurization can be designed to produce complex deformations that can be used to actuate or perform different kinds of motions. These materials commonly come into two parts that should be mixed following a prescribed ratio before being molded into their desired shape by letting them sit in this shape for a prescribed amount of time. These molds are generally 3D printed as it greatly speeds up the overall manufacturing process. A first consideration during this process is the air bubbles induced into the polymer during the mixing process, which are generally removed by a vacuum degassing process. A second consideration is that the final shape should be an airtight chamber with an internal volume which results in different methods used to obtain the shape of this internal volume during the casting process.

A common method used to create this internal volume is to cast an upper and a lower part which are then bonded together to form the sealed structure. One simple method to use a silicone adhesive such as Sil-Poxy (Smooth-On) applied between the two polymeric parts to seal them together [5,6], and this can be used to bond different polymers together (Fig. 1(a)) [7] or a polymer with a rigid part [8]. Another simple method to join two polymeric parts is to apply a layer of uncured polymer at the function of the two cured or partially cured parts (Fig. 1(b)) [9–12]. Such a method can be used also for multi-part assemblies [13]. Both methods tend to introduce minor inaccuracies at the seams, particularly when manually aligning the parts and applying adhesives or uncured polymers. These parts can also be injection molded for faster manufacturer and more consistent quality [14]. Thin material layers manufactured through spin coating can also be bonded through oxygen plasma activation [15,16].

Fig. 1

(a) Assembly of two different polymers using a silicone adhesive [7], (b) Assembly of polymer parts using a similar polymer [12], (c) Using a rigid rod to form the cavity in a chamber with a high length-to-width ratio [19], (d) Using manually bent sheet that are pulled out to form cavities within the actuator [24], and (e) Using thin rods to mold a large number of high aspect ratio soft pneumatic actuators [25] (Adapted from Refs. 7,12,24,29 on the basis of OA)

It is preferable for a tubular or similar part with a high length-to-width ratio to mold the cavity within the body with a removable object in the cavity and, after removing this object, sealing the part at both ends using either a silicone adhesive or uncured polymer [17]. It is possible for this removable object to be part of one end of the mold [18], using a rigid rod (Fig. 1(c)) [19–21], using a soft rod [22], using a 3D soft core for producing more complex cavity shapes [23], or using manually bent sheets that are easily deformed while pulling them out (Fig. 1(d)) [24]. Using an array of thin rods can help produce arrays of actuators and different methods such as gravity and electric fields can be used to create a thickness bias in the structure (Fig. 1(e)) [25].

Other casting method can be used to create an internal cavity that does not require the bonding of two or more casted parts such as lost-wax casting where a was wax negative of the internal cavity is added during the casting process and melted away during post-processing [14,26,27]. Materials other than wax can also be used in a lost-wax process such as using 3D printed acrylonitrile butadiene styrene (ABS) which can be melted away using acetone [28]. Rotating the mold during curing can also be used to obtain a one-step curing process but requires attention to thickness and geometry [29]. It also is possible to use double casting to re-orient features in the 3D space [30], or to use a multi-step casting process to produce a multimaterial part [31]. Another advanced method is to use bubble casting where air is pushed into a molded polymer to create an air channel during the curing process [32].

Casting remains one of the most prevalent and accessible manufacturing methods for soft pneumatic actuators due to its compatibility with common elastomeric materials, the wide availability of fused deposition modeling (FDM) printers for manufacturing the molds, and the ability to form complex internal geometries. Its advantages lie in the precision of mold-based designs, material uniformity, and adaptability to both simple and complex geometries. The use of bonding techniques such as adhesive sealing, uncured polymer fusion, or spin coating with plasma activation allows for versatility in multi-part assembly. However, casting is inherently a manual and multi-step process, introducing potential inconsistencies at seams, especially when parts are misaligned or adhesives are unevenly applied. While advanced methods such as bubble casting and double casting expand geometric possibilities, they require careful parameter control and often lengthy post-processing. In summary, casting-based methods offer a strong balance of material control and geometric flexibility.

3 3D Printed Pneumatic Robots

With the geometry of soft pneumatic robots and actuators affecting directly their function and performance, it follows that freeform fabrication methods such as 3D printing hold significant promises to facilitate the fabrication of the pneumatic chambers. However, although 3D printing methods can make away with the limitations imposed by molding methods which require parts to be designed as to be demolded, they also need to contend with the limitations in materials imposed by the different 3D printing fabrication methods, with limitations in terms of requiring support for overhanging parts, and with new failure modes such as delamination in layer-based printing methods.

The development of FDM 3D printers has led to the democratization of 3D printing through the use of readily available and low-cost machines. FDM functions by selectively depositing melted material layer by layer in a predetermined path. These machines use thermoplastic polymer filaments with a wide range of material compositions. The most commonly used filaments in soft pneumatic structures are thermoplastic elastomer (TPE) and thermoplastic polyurethane (TPU) as they are readily available soft and flexible filaments. The first work using FDM for soft pneumatic actuators in 2016 has demonstrated bellow-based bending actuators capable of blocked forces reaching 80 N and made into bi-chamber actuators [33]. Although the material properties of the filament can vary by manufacturer, they can also be obtained and tuned by comparing finite element analysis results with experimental results [34].

The flexibility in design provided by 3D printing methods has been demonstrated through reconfigurable helical actuator designs [35], wave-shaped patterns that minimize the deformation of the strain limiting layer or can be used to produce bidirectional bending deformations [36,37], bending actuators with integrated valve fittings [38], designs using vacuum actuation for producing bending and linear deformations [39,40], flat pouches that can be used as extension actuators [41], and monolithic soft robotic grippers [42,43]. FDM has also been used to enable advanced functionalities such as resistive sensing using a second conductive filament during the fabrication process [44], and integrated fluidic control circuits and logic gates within the structure of the soft pneumatic robot itself [45,46]. These structures often suffer from leaks resulting from small gaps caused by the shape of the path followed by the extruder when fabricating the actuator and methods such as heat treatments have been used to increase the airtightness of the structure (Fig. 2(a)) [47,48] or use a Eulerian path for depositing material [45], which means that material is deposited using a single uninterrupted trajectory. Material gradients have also been used to produce soft pneumatic robots combining soft and rigid segments using a multimaterial multinozzle FDM printer where the material composition can be varied voxel by voxel [49].

Fig. 2

(a) FDM printing following by a heat treatment process [47], (b) DIW of a soft pneumatic actuator [53], (c) Using a UV laser to cure photosensitive polymer for 3D printing of soft pneumatic actuator [59], and (d) PolyJet 3D printing of a robot with an integrated fluidic circuitry [68] (Adapted from Refs. 47,53,59,68 on the basis of OA)

Another approach like FDM is Direct Ink Writing (DIW) where a silicone elastomer is deposited from an extruder and solidified layer-by-layer. This presents several challenges due to the pot life of elastomers and the time required for a layer to solidify as well as requiring the right viscosity to allow for precise deposition without causing the deposited polymer to spread. The earliest approach to printing soft pneumatic actuators using DIW involved mixing the polymer into a syringe with an additive to increase the viscosity and using hot air on the deposited material to accelerate the silicone crosslinking [50]. Using two syringes that mix during extrusion can help solve the pot life issue stemming from pre-mixing the polymer components and produce more complex geometries such as a multi-chambered crawling robot [51]. Multimaterial DIW can produce low and high rigidity regions in the structure to produce complex deformations as those required in contractile and twisting actuators (Fig. 2(b)) [52,53].

Another approach to building soft pneumatic actuators and robots has been to use stereolithography, which consists of using an UV laser to cure photosensitive polymers in a vat such that minimal support is required. This has been used to fabricate micro-bellows and bending actuators [54–58]. Vat replacement can be used to produce multimaterial structures and enable functions such as autonomic perspiration (Fig. 2(c)) [59]. Digital light processing (DLP) is a similar method but using a projector and a mask for curing the photosensitive polymer. This method can be used to print bending actuators and millimeter scale actuators [60–62].

The last major 3D technology used to build soft pneumatic actuators and robots is material jetting 3D printing which relies on a printhead to deposit liquid resin which is then solidified by ultraviolet light exposure. Commercial machines such as the Connex 3 (Stratasys, Inc.) have enabled the fabrication of multi-DOFs bellow-based legs for crawling robots [63–65], and the multimaterial capabilities of this printer has enabled the fabrication of bellows containing both soft and rigid elements as well as one-shot printing of jamming grippers with jamming grains within the vacuum membrane [66,67]. This technology is also capable of producing very complex designs such as a structure containing multiple actuators attached to a rigid structure with embedded fluidic circuits (Fig. 2(d)) [68]. Improving the method by using a contactless approach has enabled the fabrication of complex internal structures and to build six-legged robots and a heart pump [69]. Although this 3D printing technology offers the most freedom in terms of geometry and materials, the cost of this equipment and the printing material is significantly higher than methods such as FDM.

3D printing technologies offer unmatched design freedom, enabling the fabrication of highly customized, integrated, and even multi-material soft pneumatic systems. FDM is cost-effective and widely available, making it attractive for prototyping; however, it suffers from lower resolution and issues such as delamination and air leakage, which can affect actuator performance. DIW addresses some of these limitations by allowing direct deposition of elastomers with tunable rheology, but it introduces new challenges such as material pot life and layer adhesion. SLA and DLP methods offer high resolution and complex internal geometries but are limited by the brittle nature of photopolymers and the high cost of equipment and resins. PolyJet printing stands out for its ability to integrate soft and rigid materials within a single print, enabling fully functional systems with embedded fluidics, though it remains cost-prohibitive for most laboratories. Overall, while 3D printing allows unprecedented customization and integration, each technology comes with distinct limitations in materials, cost, or mechanical reliability that must be carefully weighed.

4 Sealing-based Pneumatic Robots

Another category of bulk material which can be used for fabrication soft pneumatic robots is thin films. These can be purchased in a planar or tubular shape and which require sealing to become airtight. Some common film materials used in the fabrication of soft pneumatic robots include polyethylene (PE) and thermoplastic urethane coated with a fabric, which are a category of technical textiles. The most straightforward manner to render these films into an airtight chamber is to purchase them in a tubular shape and use a mechanical clip to seal the ends [70], but this gives little control over their geometry.

The most common method to seal these thin film structures is through heat sealing by applying a combination of heat and pressure on the area to be sealed. Using an impulse sealer is the lowest cost method for heat sealing along a line with a thickness defined by the impulse sealer’s heating element. This simple process has been used to make square actuating pouches as well as tubular structures (Fig. 3(a)) [71,72]. It is possible to add rigid or flexible skeletons inside of the structure to modulate its deformation and produce contractile or bending deformations [73,74]. When using technical textiles, the outer portion of the structure is fabric which cannot be heat sealed to other structures. One approach which has been used to attach multiple pouches made from technical textiles is to sew the pouches on the sealed edges or outside of the pneumatic chamber [75,76]. It is possible to add features such as pleats during the sealing process to produce complex deformations such as bending actuator through the uneven length of both sides of the structure [77]. Three-dimensional shapes can be manufactured by bonding the structure to obtain prismatic shapes with corners that join multiple faces [78–80]. Another low-cost option to achieve similar results but with more control over the shape of the sealed boundary is to use a hot end which can be installed onto a CNC to produce more complex geometries such as a hand containing multiple actuating pouch motors or star-shaped tubes [81,82].

Fig. 3

(a) Laser cutting and heat sealing of the air chamber using an impulse sealer [72], (b) Using a heat press for serial sealing of layers to form a sealed chamber [85], and (c) Using an adhesive to seal an origami-based inflatable robot [94] (Adapted from Refs. 72,85,94 on the basis of OA)

Another commonly used approach to seal film-based soft pneumatic actuators and robots is to use a hot press machine which simultaneously applies heat and pressure to a stack of laminated layers. Using masks over the areas to be left unbonded allows the fabrication of bellow actuators [83,84], parallel bellows for multi-DOFs actuation (Fig. 3(b)) [85], and complex kirigami pneumatic actuator shapes [86]. It is possible to use thermal adhesives to bomb surfaces that aren’t heat sealable such as the uncoated surface of technical textile [87] or to use painted-on mask layers [88]. Instead of using masks, machined stamps can be used as the heated element of the hot press to only apply pressure on certain portions of the film [89,90]. It is also possible to stack layers which different function to produce origami-like structures [91], and to assemble the heat pressed inflatable element with fabric layers to modulate their deformation [92].

Film-based soft pneumatic actuators and robots can also be hermetically sealed using other methods such as using adhesives to seal the structure [93], using double-sided tape to attach rigid facets onto a soft film (Fig. 3(c)) [94], hot air welding by melting the surface of the material using a flow of hot air [95,96], using ultrasonic welding [97], using laser welding [98,99], and using laser cut features onto the film to modulate the deformation [100]. Each of these methods have their own advantages but may require equipment not as readily available as the methods mentioned in previous paragraphs.

Sealing-based manufacturing methods provide a low-cost and scalable approach to constructing soft pneumatic actuators, particularly suited to planar or tubular geometries. Heat sealing using impulse sealers or hot presses is simple, fast, and reliable for producing airtight chambers from thin films. Impulse sealing is the lowest cost option to manufacturing soft pneumatic actuator. The use of technical textiles enhances durability and allows complex deformations when combined with pleats or prismatic shaping. However, these methods are limited in terms of geometry and integration with other elements. Techniques such as adhesive bonding, ultrasonic welding, and laser welding broaden the manufacturing toolkit but introduce complexity, equipment costs, or require skillful application. Compared to casting or 3D printing, sealing methods prioritize simplicity and cost over customization and mechanical precision. Nevertheless, their speed and suitability for batch production make them ideal for applications requiring lightweight, low-profile actuators.

5 Other Methods

There are a few other methods of interest for building soft pneumatic actuators and robots that should be mentioned. One of these methods is weaving off-the-shelf pneumatic tubes with constraints. These tubes can be attached to the constraints using silicone adhesives [101], or woven onto fabrics [102]. Another simple approach is to insert a balloon into a straw with notches such that the inflation of the balloon causes a joint-like deformation of the straw at the location of the notches [103]. A technique to decouple the inflation function of the structure from its deformation function. This is done by inserting a bladder inside of a second structure which either gives mechanical resistance to the structure or shapes the deformation of the structure. In the first of these cases, the outer layer can be sewn or sealed without considering minor holes or leaks in the structure while the internal layer should simply prevent leaks (Fig. 4(a)) [104–106]. For the second case, a plastic skin can also be used to modify the inflation pattern of the inner bladder and produce a bending deformation [107]. These techniques stand out for their modularity, low cost, and potential for rapid prototyping. However, they generally offer lower precision and require empirical tuning, which may limit repeatability and mechanical performance. As such, they are best suited for exploratory designs or where soft, organic motion is more important than geometric or force precision.

Fig. 4

(a) Insertion of a balloon inside of a fabric outer shell to decouple the inflation function from the mechanical function [106], (b) Using different stitching patterns to encode the function of the structure [106], and (c) 3D knitting machine for soft pneumatic robots [110] (Adapted from Refs. 106,110 on the basis of OA)

Another technique used to produce complex deformations of a soft pneumatic actuator or robot using a bladder is to use textiles or knitted materials as the exterior surface that defines the deformation. This can be done simply by using materials with difference elasticity to produce bending curvatures [108], by changing the knitting pattern of the structure [109], or by changing the stitching pattern applied during sewing of the surfaces (Fig. 4(b)) [106]. The anisotropy of woven materials can also be used to tailor the deformation of a knit surface by changing the pattern throughout the structure and produce complex deformations (Fig. 4(c)) [110,111]. It is also possible to program additional capabilities into the exterior surface such as by embedding sensing materials into its structure [112]. However, these methods often require tedious manual labor or complex machinery which would make them more suited for batch production with industrial machines rather than for exploration and low-cost small batch manufacturing.

6 Conclusion

The manufacturing of soft pneumatic actuators represents a critical area of development within the broader field of soft robotics, which seeks to create flexible, adaptable systems capable of performing complex tasks in a variety of environments. These actuators, which rely on pressurized air or fluid to enable movement, hold immense potential for applications across multiple industries, including healthcare, where they can be used in medical devices such as assistive wearables, rehabilitation equipment, and minimally invasive surgical tools. They are also valuable in the field of soft gripping for delicate tasks in manufacturing, agriculture, and food processing, as well as in the creation of lifelike robotics for human-robot interaction. Given their versatility and potential, advancing the fabrication methods for these actuators is essential to moving these innovations from the research stage to practical, real-world use.

This review has presented four major manufacturing methodologies, namely casting, 3D printing, sealing-based methods, and other alternative fabrication techniques, each offering distinct advantages and trade-offs. Casting-based methods are widely used due to their compatibility with soft elastomers and the precision they offer in shaping internal air channels, though they often require multi-step bonding. 3D printing techniques, including FDM, DIW, stereolithography, and material jetting, allow for highly customizable geometries and multi-material integration, yet can suffer from issues like layer delamination and high equipment costs. Sealing-based methods, relying on films and heat or adhesive bonding, provide a low-cost and scalable approach but can limit design complexity. Other methods, such as bladder-based and textile-constrained systems, enable novel deformation mechanisms and modular construction, but often require careful integration of materials with different mechanical properties. A comparison of the different techniques is presented in Table 1. It was demonstrated that the specific manufacturing method chosen to fabricate soft pneumatic actuators and robots introduces both limitations and opportunities in the design, affecting key factors such as flexibility, durability, response time, and load-bearing capabilities. These design considerations are critical, as they ultimately shape the actuator’s functionality and adaptability to different applications.

Table 1

Comparison of the different manufacturing techniques

Future research should continue to focus on developing more efficient, scalable, and reliable fabrication techniques while addressing current limitations in material performance and design constraints. There is a need to explore new materials with enhanced elasticity, strength, and responsiveness, as well as manufacturing processes that can accommodate complex geometries and allow for higher precision. Each manufacturing method presents very different constraints but also unique opportunities for customization in design, which can be better harnessed through further research and technological advancements. By overcoming these challenges, the field of soft robotics will move closer to realizing its full potential across a wide range of industries, from healthcare and industrial automation to wearable technologies and beyond.

Notes

Acknowledgement(s)

This work was supported by the National Research Foundation of Korea (NRF) funded by the Korean government (Ministry of Science and ICT) (No. RS-2024-00457555).

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Biography

Altair Coutinho was born in Belem, Brazil. He received the B.Eng. degree in control and automation engineering from Estacio de Sa University, Belem, Brazil, in 2017. He is currently working toward the master's/Ph.D. combined degree in mechanical engineering with the Soft Robotics Laboratory, School of Mechanical Engineering, Sungkyunkwan University. His research focuses on hybrid soft/rigid pneumatic artificial muscles, with applications in robot-human interaction, as well as the development of novel soft robotics mechanisms for advanced actuation and control.

Jae Hyuck Jang was born in Daejeon, Republic of Korea. He received the B. Eng. in Electronic and Control Engineering from Hanbat National University in Daejeon, Korea in 2019. He is pursuing his Master/PhD Combined Degree at the Soft Robotics Laboratory in Sungkyunkwan University. His research interests include soft robotics mechanisms, pneumatic actuator, variable stiffness mechanism, wearable application and gripper.

Yeong Jae Park was born in Yeosu-si, South Korea. He received the B.Eng. degree in mechanical engineering from Myongji University, Yongin-si, South Korea, in 2019. Currently, he is pursuing the combined master’s and Ph.D. degree with the Soft Robotics Laboratory, Sungkyunkwan University, Suwon-si, South Korea, under the supervision of Prof. Hugo Rodrigue. His research interests include morphing mechanisms, inflatables tubes and polymers structures and Shape Memory Alloy applications.

Sewoong Chung was born in Seoul, Republic of Korea. He received the B.Eng. degree in mechanical engineering from Sungkyunkwan University, Suwon, Republic of Korea, in 2020, and currently pursuing combined Master/Ph.D. degree at the Soft Robotics Laboratory, Sungkyunkwan University, Suwon-si, Republic of Korea, under the supervision of Prof. Hugo Rodrigue. His research interests include inflatable actuators and 3D printed soft robotics.

Hugo Rodrigue was born in Montreal, Canada. He received the B.Eng. degree in mechanical engineering from McGill University, Montreal, QC, Canada, in 2008, and the Ph.D. degree in mechanical and aerospace engineering from Seoul National University, Seoul, South Korea, in 2015. Since 2016, he has been an Associate Professor with the School of Mechanical Engineering, Sungkyunkwan University, Suwon, South Korea. His research interests include soft robots and actuators, soft optical waveguides, and hybrid soft/rigid structures. Dr. Rodrigue serves as Associate Vice President of the IEEE RAS Technical Activities Board, as Co-Chair of the Technical Community on Soft Robotics, and as an Associate Editor for IEEE Robotics and Automation Letters as well as International Journal of Robotics Research. He is serving as the Program Chair for the IEEE International Conference on Soft Robotics in 2025.

Article information Continued

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Method category	Materials used	Advantages	Limitations	Design complexity
Casting	Silicone elastomers (e.g., PDMS, EcoFlex)	High material compatibility; detailed internal cavities possible	Multi-step process; alignment/sealing errors	Moderate to high
3D printing	Flexible filaments, curable inks and resins	High spatial resolution; multimaterial possible complex geometries	Limited material selection; limited material properties	High to very high
Sealing-based	Thin films (PE, TPU, textiles)	Low cost; scalable; easy to implement	Limited 3D geometry; heat-sealing restrictions on some textiles	Low to moderate
Other methods	Balloons, off-the-shelf tubes, textiles	Modular, intuitive designs; decoupling of functions	Less precision; dependent on commercial parts	Low to moderate